Mechanistic Understanding of Li Transport in Rechargeable Batteries

Electrodes in rechargeable batteries undergo complex electrochemically-driven phase transformations upon driving Li ions into their structure. Such phase transitions in turn affect the reversibility and stability of the battery. It is of prime importance to better understand how Li ions transport within the host electrodes and what phase transitions are triggered during such interaction. This presentation gives an overview of the PI’s research program on in situ transmission electron microscopy (TEM) of battery materials.  Various anode materials including SnO₂, Zn-Sb were subjected to lithiation process and the transport of Li ions was visualized within their atomic structure. For SnO₂ nanowires, it was observed that the Li ion transport results in local strain development preferably along (200) or (020) plans and [001] crystallographic directions. Anisotropic plastic deformation was also observed along [010] directions of MnO₂ nanowires. Zn-Sb alloys also exhibit a new cubic alloying phase Li₂ZnSb that form by intermixing of the ABAB atomic ordering in hexagonal LiZnSb due to Li inclusion in their lattices.